1. Field of the Invention
The present invention relates to an apparatus for electrically grounding a coaxial cable and, more particularly, to a multi-port ground block useful in the electrical connection and grounding of a receiver, such as satellite dish, and a plurality of coaxial cables.
2. Description of Related Art
The use of satellite dishes to receive cable TV and radio signals from orbiting satellites has expanded significantly in recent years. Direct Broadcast Satellite (“DBS”) is broadcast by medium and high powered satellites operating in the microwave Ku band. These high powered, high frequency satellites make it possible for the signals to be picked up on a small dish. Digital compression makes it possible to have many channels on a single satellite. The current major DBS systems that are operating in the USA are DIRECTV and DISH Network. The DIRECTV and DISH Network systems both have 18 inch satellite dishes. One of the big advantages of DBS systems is that the small dish does not have to move.
Signals received by a satellite dish are often carried from the dish on conventional coaxial cables. In a typical coaxial cable installation, coaxial cable is run from the satellite dish to the approximate point of entry into the building where it is cut and provided with a conventional coaxial connector including a threaded end sleeve. Similarly, a coaxial cable is run from a tuner located within the building through the building wall and provided on its outside end with an identical standard end fitting. Connection between the terminated ends of the main incoming cable and the cable from within the building is made by utilizing a coaxial cable junction block.
Conventional junction blocks are metallic devices adapted for in-line connection of coaxial cables. Junction blocks typically include a pair of axially aligned and oppositely extending threaded connector studs to which the respective threaded sleeves of the cable end fittings are attached thereby connecting the two sections of coaxial cable. In addition, dual port junction blocks having a pair of axially aligned and oppositely extending connector studs are used in applications involving multiple coaxial cables.
With the use of coaxial cable junction blocks, installers are able to install interior and exterior runs of coaxial cable independently of one another and connect the interior and exterior runs at the junction block. The junction block, however, must be separately attached to the outer wall or other portion of the building and, additionally, a separate grounding connection must be made from the block to a suitable ground, such as an electrical conduit, pipe, or the like. Thus, the installer must drill holes or otherwise provide some means for attachment of the junction block to the building and must additionally repair and attach a separate ground lead between the junction block and the grounded conduit or the like. Providing an appropriate attachment of the junction block to the building may be difficult or objectionable to the owner. In addition, providing a separate grounding connection is also time consuming and requires the use of additional materials.
Grounding is the intentional connection to earth's electrical potential (e.g. ground potential) through an electrical connection of low impedance. The purpose of grounding is to assist in preventing the destruction of electrical components, and property damage from superimposed voltage from lightning and voltage transients. In addition, grounding helps in reducing static charges on equipment surfaces there ensuring proper performance of sensitive electronic equipment.
One of the primary purposes of grounding communications equipment to the earth is to reduce high voltage from lightning from entering into the building or structure via metal raceways or cables. If the metal parts of communication equipment are not grounded in accordance with the NEC, much of the high energy from the lightning strike will be dissipated within the structure, which can result in equipment and property damage as well as the potential for electric shock. Grounding also helps in reducing the build-up of static charges on equipment and material and establishing a zero voltage reference point to ensure proper performance of sensitive communications equipment.
As a result of increased use of coaxial cables in satellite and cable TV applications, and the importance of electrically grounding those systems, the prior art reveals a number of advancements and improvements directed to coaxial cable ground blocks.
U.S. Pat. No. 6,297,447, issued to Burnett et al., discloses a ground connection bracket for securing coaxial cables to a grounding surface. The device includes two clamping members connected along a common edge by an integral hinge such that they may be squeezed together around the cables thereby gripping them. Each of the clamping members is composed of a generally flat, rectangular panel and has two parallel side walls extending therefrom along edges perpendicular to the hinge edge. A hole passes through the panel of one of the clamp members to receive a bolt for fastening the bracket to a grounding surface. One or more coaxial cables are inserted between the clamping members so as to extend through the notches. Contacts are disposed on the clamping members to contact conductive portions of the cables and the bracket is secured to the electrical ground.
U.S. Pat. No. 5,829,992, issued to Merker et al., discloses a single port device for grounding or electrically bonding a cable television connector and eliminating a jumper wire connection, comprising a television cable connector having a threaded large diameter portion tapering to a threaded small diameter end portion; a planar block of conductive material having various configurations connecting the connector parallel to a ground/bond wire. The block can have a plurality of throughbore sets for grounding/bonding a plurality of cable television connectors. Merker et al. further discloses a multi-port embodiment wherein the ports are aligned in linear space relation.
U.S. Pat. No. 4,875,864, issued to Campbell, discloses a coaxial cable junction block provided with an adjustable mounting strap for direct attachment to a tubular grounding member. The junction block is intended to provide a direct ground connection for the block and attached outer conductors of the interconnected coaxial cable sections, eliminating the need to provide mounting holes in a building side wall or the like, and direct grounding of the cable sections without the need for a separate ground wire connection.
U.S. Design Pat. Nos. D459,304, and D459,306, each issued to Malin, disclose ornamental designs for a single-port and dual-port ground blocks. U.S. Design Pat. No. D459,305, also issued to Malin, discloses an ornamental design for a dual-port ground block wherein the coaxial cable connectors are in spaced linear relation.
While the coaxial cable ground blocks disclosed in the background art appear generally suitable for certain applications there remain a number of structural and functional limitations present in the prior art devices. A significant limitation involves the number of coaxial cables that the prior art devices are designed for use with. More particularly, most ground blocks are either single port or dual port, and are thus only capable of use with one or two coaxial cables. Accordingly, a plurality of ground blocks must be used in systems having more than one or two coaxial cables thereby requiring multiple ground wire connections. In addition, the prior art multi-port ground blocks disclosed include ports that are closely spaced and linearly aligned thereby increasing the difficulty of connecting the coaxial cables. Accordingly, there exists a need for an improved multi-port ground block adapted to provide easy connection and grounding of four coaxial cables.